EXOSURF Neonatal is a protein-free synthetic lung surfactant whereas SURVANTA is a natural surfactant extracted from minced bovine lungs. EXOSURF Neonatal was approved for release by the FDA on August 3, 1990. SURVANTA is currently available for use under treatment IND. FDA approval for SURVANTA is anticipated after this trial has begun. The object of this randomized clinical trial is to compare the efficacy of thest two surfactants. Each surfactant is to be used in a manner consistent with the manufacturer's recommendations.